Abstract
Purpose :
Though 5% povidone-iodine (PI) is frequently used as an ocular anti-septic, there is a lack of consensus regarding the effects of PI concentration, storage after opening, and compounded preparation on PI anti-sepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PI’s inhibition of common causes of post-procedural eye infection.
Methods :
Inhibition of microorganism growth was measured in-vitro as a function of active PI exposure time (15/30 seconds, 1/3/5 minutes). In control experiments, PI was inactivated before microorganism exposure. Tested PI solutions varied in concentration (0.6/5/10%), length of storage after opening (0/7/30 days), and preparation (commercial/compounded from stock PI and balanced salt solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, S. aureus (methicillin-resistant and sensitive), and C. albicans.
Results :
PI solutions inhibited all bacterial growth by 3 minutes and all fungal growth by 15 seconds. Compared to 5% PI, 0.6% PI was less effective in inhibiting S. viridans growth (1000±0 colonies vs. 7±7 at 30 seconds, P < 0.0001; 916±104 vs. 0±0 at 1 minute, Fig. 1a), but more effective in inhibiting both P. aeruginosa (29±20 vs. 1000±0 at 15 seconds, P = 0.004, Fig. 1b) and methicillin-resistant S. aureus (59±40 vs. 866±58 at 1 minute, P = 0.012, Fig. 1c). No differences were seen in methicillin-sensitive S. aureus inhibition across concentrations (Fig. 1d). In-house compounded PI solutions and solutions stored for 7 or 30 days showed no decreases in efficacy across all organisms when tested against commercial and newly-opened PI, respectively.
Conclusions :
Concentration of PI solution affects anti-septic efficacy within 1 minute of exposure, but all solutions performed equivalently at 3 minutes. Compounded preparation and storage length after bottle opening were not significant factors for PI anti-sepsis.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.